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From: Ard Biesheuvel <ardb+git@google.com>
To: linux-kernel@vger.kernel.org
Cc: Ard Biesheuvel <ardb@kernel.org>,
	Jason Andryuk <jason.andryuk@amd.com>,
	 Juergen Gross <jgross@suse.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	x86@kernel.org,  xen-devel@lists.xenproject.org
Subject: [PATCH 3/5] x86/pvh: Omit needless clearing of phys_base
Date: Thu, 26 Sep 2024 12:41:17 +0200	[thread overview]
Message-ID: <20240926104113.80146-10-ardb+git@google.com> (raw)
In-Reply-To: <20240926104113.80146-7-ardb+git@google.com>

From: Ard Biesheuvel <ardb@kernel.org>

Since commit

  d9ec1158056b ("x86/boot/64: Use RIP_REL_REF() to assign 'phys_base'")

phys_base is assigned directly rather than added to, so it is no longer
necessary to clear it after use.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/x86/platform/pvh/head.S | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/arch/x86/platform/pvh/head.S b/arch/x86/platform/pvh/head.S
index f09e0fb832e4..592747f2d731 100644
--- a/arch/x86/platform/pvh/head.S
+++ b/arch/x86/platform/pvh/head.S
@@ -179,13 +179,6 @@ SYM_CODE_START_LOCAL(pvh_start_xen)
 	ANNOTATE_RETPOLINE_SAFE
 	call *%rax
 
-	/*
-	 * Clear phys_base.  __startup_64 will *add* to its value,
-	 * so reset to 0.
-	 */
-	xor  %rbx, %rbx
-	movq %rbx, phys_base(%rip)
-
 	/* startup_64 expects boot_params in %rsi. */
 	lea pvh_bootparams(%rip), %rsi
 	jmp startup_64
-- 
2.46.0.792.g87dc391469-goog


  parent reply	other threads:[~2024-09-26 10:41 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-26 10:41 [PATCH 0/5] x86/xen: Drop absolute references from startup code Ard Biesheuvel
2024-09-26 10:41 ` [PATCH 1/5] x86/pvh: Call C code via the kernel virtual mapping Ard Biesheuvel
2024-09-26 10:55   ` Ard Biesheuvel
2024-09-26 20:29     ` Jason Andryuk
2024-09-26 10:41 ` [PATCH 2/5] x86/pvh: Use correct size value in GDT descriptor Ard Biesheuvel
2024-09-26 14:29   ` Andrew Cooper
2024-09-26 20:32   ` Jason Andryuk
2024-09-26 10:41 ` Ard Biesheuvel [this message]
2024-09-26 20:35   ` [PATCH 3/5] x86/pvh: Omit needless clearing of phys_base Jason Andryuk
2024-09-26 10:41 ` [PATCH 4/5] x86/xen: Avoid relocatable quantities in Xen ELF notes Ard Biesheuvel
2024-09-27  1:46   ` Jason Andryuk
2024-09-27  5:49     ` Ard Biesheuvel
2024-09-27  7:21       ` Ard Biesheuvel
2024-09-26 10:41 ` [PATCH 5/5] x86/pvh: Avoid absolute symbol references in .head.text Ard Biesheuvel
2024-09-27 22:12   ` Jason Andryuk

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